1. Field of the Invention
The invention relates to an aerodynamic wind propulsion device, particularly for watercrafts, comprising an aerodynamic wing being connected to a steering unit located below the aerodynamic wing via a plurality of tractive lines, at least one pair of two active steering lines being connected to the aerodynamic wing at two points in distance to each other and being coupled to at least one drive unit at the steering unit, a tractive cable, a first end of the tractive cable being connected at the steering unit to at least two of the tractive lines and a second end of the tractive cable being connected to a base platform, the aerodynamic wing having an aerodynamic profile which generates an uplift force in the direction of the tractive cable when the airflow direction is about perpendicular to the tractive cable.
A further aspect of the invention is related to a method for controlling an aerodynamic wind propulsion device, particularly for watercrafts, comprising the steps connecting an aerodynamic wing to a steering unit located below the aerodynamic wing via a plurality of tractive lines, connecting at least one pair of two active steering lines to the aerodynamic wing at two points in distance to each other and coupling said at least one pair of active steering lines to at least one drive unit at the steering unit, connecting a first end of a tractive cable at the steering unit to at least two of the tractive lines and connecting a second end of said tractive cable to a base platform, and applying steering forces to said at least one pair of active steering lines. Description of Related Art including information disclosed under 37 CFR 1.97 and 1.98
The following patents and publications were cited in an International Search Resort against the priority application as defining the general state of the art which is not considered to be of particular relevance: WO2005/100147 A (Oct. 27, 2005); DE 10 2004 054097 A1 (May 11, 2006); GB 2,096,946 A (Dec. 1, 1982); U.S. Pat. No. 7,287,481 B1 (Oct. 30, 2007).
Today, carbon-based fuels like diesel or heavy fuel oil (HFO) are used as a key resource for propelling nautic vessels. Mostly, diesel engines are used to provide the driving force for the vessels. With increasing costs for such carbon-based resources it becomes attractive to apply alternative methods for providing the driving force for nautic vessels.
WO 2005/100147 A1 discloses a positioning device for controlling a wing element which is connected via a tractive cable to a ship to serve as main or auxiliary drive. Such propulsion systems based on wing elements flying at high altitude and pulling the ship via a tractive force require large-scale wing elements and the control of such wing elements is a challenging task. In WO 2005/100147 A1 it is proposed to veer out or haul in the tractive cable in response to the flight condition of the wing element. Whereas by such a control mechanism a certain degree of flight control can be achieved, it is not sufficient to control the wing element in all flight conditions, in particular when the wind changes its strength or direction significantly.
To improve steerability of such wing elements in difficult wind conditions it is known from WO 2005/100148 A1 to couple a steering unit close below the wing element via a number of control lines and to connect the wing element to the nautic vessel via such a steering unit by a tractive cable extending between the nautic vessel and the steering unit. By this, control of the wing element can be improved but it is still a challenging task to control the wing element and specifically to steer the flight path of the wing element.
WO 2005/100149 A1 proposes various sensors to improve control of a wing element towing a nautic vessel. Whereas these and the former techniques may improve the steerability of aerodynamic wing elements it remains still a quite challenging task to efficiently steer an aerodynamic wing element and control its flight path and conditions in an efficient way.
To improve steerability during starting and landing manoeuvres, WO 2005/100150 proposes a telescopic mast erected onto the foredeck of the nautic vessel close to the fixing point of the tractive cable coupling the wing element to the nautic vessel. Using such mast, the wing element can be directly coupled to the top of the mast. Whereas such a technique may significantly improve manoeuvrability of the wing element during starting and landing procedure, the challenging task to improve the steerability of the wing element in various flight conditions and to improve the efficiency of such a steering technique remains.